A brush head, a method and an apparatus for producing the brush head are disclosed in U.S. Pat. No. 4,869,277, commonly assigned herewith. The brush head has a sufficiently thickened base to allow effectively securing all the fibers to the bottom plate such that the brush is suitable for us in an ordinary clinical dental drill or in a battery driven home care device. Brushes produced according to the prior art suffered from the inability to insure a constant amount of fiber material for melting to form the bottom plate, in that it was difficult in practice to obtain precisely the same abutment pressure on the tool every time. This was believed to occur because the surface of the fibers was very smooth and displacement tends to occur between the feed mechanism and the fiber bundle. This gives different material amounts for the formation of the bottom, and if the fibers slide back in the feed mechanism retainer, the amount of material available is insufficient to form a bottom plate which holds all the fibers together. Thus such brushes suffered from the fibers working loose with consequent inconvenience for the user of the brush. Also, the bottom plate may become oblique in that the material is distributed unevenly at the bottom which provides poor contact with a retaining device to which the brush head is attached.
The brush head, method and apparatus for producing the brush head disclosed in U.S. Pat. No. 4,869,277 overcame these problems by assuring that the fiber bundle, during melting, is constantly carried towards a tool (or, visa-versa, the tool carried towards the fiber bundle) so that an extended bottom plate is formed, whereafter the fibers are cut at a desired length and the extended bottom plate is removed to provide the finished brush head.
While substantial success has been achieved using the brush head, method and apparatus of the '277 patent, additional improvements have been made which increase the adaptability of the brush head for use in other applications.